Bridging plug



C. C. BROWN BRIDGING PLUG Sept. 20, 1960 3 Sheets-Sheet 1 Filed Aug. 8, 1955 C/ce/v C. Brow/7 INVENTOR.

Sept. 20, 1960 c. c. BROWN 2,953,206

BRIDGING PLUG Filed Aug. 8, 1955 V r 3 Sheets-Sheet 2 C/ce/a C. Brow/7 INVENTOR.

Sept. 20, 1960 c. c. BROWN 2,953,206

BRIDGING PLUG Filed Aug. 8, 1955 3 Sheets-Sheet 3 KETMB 2%??74A l v ma l2 C/tera C. Brown 1 i INVENTOR.

United States Patent Q r:

BRIDGING PLUG Cicero C. Brown, Brown Oil Tools, Inc., 2216 Campbell St., Houston, Tex.

Filed Aug. 8, 1955, Ser. No. 526,994

9 Claims. (Cl. 166-125) This invention relates to a plugging device commonly termed bridging plug for plugging well pipes in a well bore, and particularly to a form of bridging plug adapted to be run on a wire line.

In oil and gas wells, it is often necessary to conduct repair or treating operations within the well bore at locations and under conditions which make it desirable or necessary to remove the tubing string, that is, the inner or production string of pipe, to some point at or below the point at which the operation is to be conducted. Ordinarily, this would require killing the well in some suitable manner, as by pumping mud into the well, in order to cut-ofi the flow of well fluid through the production pipe or tubing while the repair or treating operations are being conducted within the well bore. Killing the well in this manner may result in permanent damage to the well, and other means of stopping the flow are to be preferred.

Accordingly, it is a primary object of the present invention to provide an improved form of bridging plug which may be removably inserted at any desired point in a well pipe to effectively close the bore thereof, and which may be run on a wire line.

Another object is to provide a bridging plug for use particularly in comparatively small diameter well tubing.

A more specific object is to provide a bridging plug, including, anchor means for securing the plug body in the bore of a well pipe, and seal means positioned above the anchor means for forming a fluid-tight seal between the plug body and the well pipe, the positioning of the seal means above the anchor means serving the additional function of preventing detritus or foreign matter from the well above the plug from fouling the anchor means.

A further object is to provide a plugging device for well tubing which includes a seating nipple adapted to be installed in the tubing string for receiving the plug member and having means co-operating with the inserted plug member to anchor the latter in the seating nipple.

Still another object of this invention is to provide a plugging device for well tubing which includes a releasable coupling adapted to form a connection between sections of a well pipe string, one member of said coupling forming a seating nipple to receive and anchor the plug member of the device.

Other and more specific objects and advantages of this invention will become apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiinent in accordance with this invention.

In the drawing:

Fig. l is a longitudinal View, partly in section, of a portion of a well pipe string, such as a tubing string, showing the manner in which the plugging device in accordance with this invention is installed therein;

Figs. 2A and 23, together, comprise a longitudinal, partly sectional view of the plugging device in accordance with this invention, the parts thereof being shown in the positions occupied when being run into the pipe S 1 Fig. 3 is a cross-section along line 33 of Fig. 2B;

Patented Sept. 20, 1960 Figs. 4A and 4B, together, constitute a view similar to Figs. 2A and 23, showing the parts of the device in anchored position in the pipe string;

Fig. 5 is a cross-section view along line 55 of Fig. 4B; and

Fig. 6 is an enlarged view of the upper end of the plugging device, showing, in broken lines, the outline of a conventional fishing tool secured thereto for removing the device from the well.

Referring first to Fig. 1, there is shown a pipe string, such as a tubing string 1, in which is interposed a coupling member, designated generally by the numeral 2, comprising a seating nipple 3 and a coupling sleeve 4 which is releasably connected to seating nipple 3 by means of an inwardly projecting lug 5 which is engaged in a bayonet or J-type slot 6 formed on the exterior of seating nipple 3. Coupling sleeve 4 is provided with internal packing 7 to form a fluid-tight seal about the exter'ior of nipple 3 when the coupling members are connected together in order to prevent leakage of fluid to the exterior of the tubing string. Releasable coupling member 2 will ordinarily be installed as a permanent part of the pipe string when the latter is first installed in the well in order to be available for use with the plugging device when the latter is required at a subsequent time during the life of the well. A plugging device, designated gen erally by the numeral 8, is run into tubing string 1 on a wire line 9, a set of wire line jars of any conventional form, designated generally by the numeral 10, being in terposed between wire line 9 and plugging device 8.

Referring now to Figs. 2A, 2B and 3, the seating nipple 3 is shown in greater detail, having a central bore 11 internally threaded at its lower end at 12 to receive the externally threaded pin 13 forming the end of a section of pipe string 1 into which the seating nipple is connected. Intermediate its ends, the bore wall of nipple 3 is provided with an annular recess 14 having upwardly and downwardly tapered upper and lower end walls 15 and 16, respectively, defining longitudinally spaced tapered shoulders. The bore wall of seating nipple 3 is also pro' vided with an internal shoulder 17 spaced downwardly slightly from lower end wall 16.

The plugging device, proper, comprises the generally tubular body 18 closed at its lower end by a cap 19 threadedly secured at 20 to the lower end of body 18, cap 19 preferably having a conical guide nose 21. Intermediate its ends body 18 is provided with a plurality of angularly spaced radial openings 22 in each of which is mounted a radially movable arcuate slip member 23 having relatively smooth inner and outer a-rcuate surfaces 24 and 25, respectively. The inner and outer edges at the upper and lower ends of the slip members, are chamfered at 26 and 27, respectively. The portion of body 18 above openings 22, is reduced somewhat in 6X- ternal diameter at 28 to provide the downwardly facing shoulder 28a. A series of packing rings 29, preferably of the chevron or other pressure sealing type, are positioned about the reduced portion 28 of body 18 and are compressed against shoulder 28a by means of a sleeve nut 30 which is threaded on to the reduced diameter portion 28. The portion of body 18 below openings 22 is reduced in diameter to form the downwardly facing tapered shoulder 31, which is adapted to abut against shoulder 17 in the seating nipple in order to limit the inward movement of the plugging device in the bore of seating nipple 3 to a position adapted to dispose slips 23 opposite recess 14. One or more ports 32 positioned in the wall of body 18 below shoulder 31 provide communication between the interior and the-exterior of the body.

The bore of body .18 is enlarged somewhat in diameter from a point near its upper end, defining the downwardly facing annular shoulder 33,to' a point slightly below '7 below ports 32.

. 3 ports'32. Coaxially disposed tohave a close sliding fit in the bore of body 18 is a generally tubular mandrel 35 which extends upwardly above the upper end of body 18.. Mandrel 35 is formed intermediate its ends to provide a radially enlarged expander portion 36, the upper end of' the latter defining the upwardly facing annular shoulder 37 adapted to'abut shoulder 33 when the mandrel is in' the inactive or retracted position. The lower end of enlarged portion 36 is downwardly and inwardly tapered to form the sloping annular shoulder 38. The

length of enlarged portion 36 is made such that when shoulder 37 is in engagementwith shoulder 33, the enlarged portion will be above and'out of. engagement with slips 23. The portion 35a of the mandrel which extends below expander portion 36 has a length such that when the mandrel is iii-the retracted position (Fig. 2B), portion 35a will extend from a point above openings 22 to a point below ports 32'and-into sliding engagement with the portion 18a ofthe bore wall of body 18 which is The external diameter of mandrel portion 35a is made such that when the mandrel is in the retracted positiomsuflicient radial space will be provided behind slips 23 that the latter may move radially inwardly a suflicient distance to permit outer faces 25 of the slips to be substantially flush with, or' radially inwardly of, the outer perimeter of body 18. An annular seal packing 39 is positioned between the lower end portion'of mandrel portion 35a and the adjacent portion of the bore wall of body 18 to form a fluid-tight slidable seal'b'etween these members at a point'below ports 32. A similar seal 40 is provided between mandrel 35 and body'18 at a point above shoulder 33. Upper circulation-ports-41-41 (Fig. 2A) are provided through the f wallof'the portion of mandrel 35 which extends out of the upper 'end of body 18 to provide communication between the interior and the exterior of the mandrel, and

lower circulation ports 42 are provided through the wall of mandrel portion 35aabove the lower end thereof to provide fluid communication between the interior of the mandrel and the bore of body 18 when the mandrel is in its retracted position. The upper end of mandrel 35 i (Fig. 2A) is externally threaded to receive a tubular cap 43, the lower end of which defines a downwardlyfacing annular shoulder 44 and the upper end 45 has a frustoconical shape. r

The upper end-of body 18 isformed with a short upwardly extending neck 45 slidably surrounding mandrel 35 and having a lesser externaldiameter than body 18 to define the, upwardly facing annular shoulder 46. A a tubular connector sleeve 47 has its lower end extending about the exterior of neck 45 and resting on shoulder 46 and is releasably secured to neck 45 by means'of a suitable releasable connection, such as a breakable shear pin 48'which is inserted between the engaged surfaces of neck 45 and sleeve 47. Connector sleeve 47 encloses the portion of mandrel 35 which extends above the upper end of plug body 18 and the sleeve extends somewhat above the upper end of cap 43, being provided near its upper end with a downwardly facing'internal annular-shoulder 49 spaced above cap 43. The bore of connector sleeve 47 dimensioned to have a close sliding V' fit with the exterior of cap 43yand is releasably secured to mandrel'35 by a suitablereleasable connection, such as a conventional.

breakable shear pin-50, inserted between the adjacent surfaces of cap-43 and the bore wall of sleeve 47. Oirculation passages 51-51 are provided in the wall of sleeve 47 to provide fluid communicationbetween the exterior thereof and'the portion of the interior thereof between the lower endof cap 43 and neck 45.

. A cylindrical-stem 52 extends into the upper end of 7, connector sleeve 47 andis provided atitslower end with a cylindrical enlargement or head 53 defining an upwardly i facing annular shoulder "54 adapted to abutshoulder 49. The lower endof head 53 is provided with frusto-conical socket 55' adaptedto snuglyreceive the similarly. shaped of stem 52 is threaded'at 56 to be received in a threaded socket 1104: provided in the lower end of jars 10.

The plugging device operated in the following manner: Bridging plugv 8 is assembled with the parts thereof in the relative positionshown particularly in Figs. 2A and 2B. In this position it will beseen that mandrel 35 is locked in the retracted position relative to plug body 18 by means of shear pin which secures the mandrel to connector sleeve 47. In this position expander 36 will be elevated aboveslips 23 so that the latter are free to move inwardly of the plug body so that the plug body may be freely inserted in the setting nipple. In the retracted or inactive position of the mandrel it will be seen that circulationports 42 will be above seal 39, hence there will be open fluid communication between ports 3'2 and 42, and between ports 41 and 51 to permit passage of fluid through the bore of mandrel 35 when the device is lowered through tubing string and .the string of tools having the wire line jars 10 inserted therein for use in connection with the operation.v The string of tools, so assembled, is then lowered through tubing 1 from the surface until'plug body 18 enters seat ing nipple 3 and shoulder 31' come into engagement with shoulder 17 in the seating. nipple (Fig. 2B), which will stop further movement of the plug body and position slips 23 opposite recess 14 in the seating nipple. In this position, being that illustrated particularly in Figs. 2A and 2B, packing 29 will be placed in sealing engagement with the bore wall of seating nipple 3 above recess 14. With further inward movement of the plugging device thus stopped, downward jarring by means of jars 10 will be applied through stem 52 against cap 43 in order to break shear pin 50 to thereby release the mandrel from its engagement with plug body 18. Breaking of the releasable connection between the mandrel 35 and plug body 18' will allow the mandrel to be lowered relative to the plug body whereby expander 36 will be caused to descend relative to the plug body until tapered shoulder 38 engages tapered shoulder 26, on the slips, urging the latter radially outwardly into recess 14 and allowing the expander to move downwardly inside the slips. The inner end wall of nose 21 of the plug body serves as a limit stop for the lower end of mandrel 35 (Fig. 4B) to position expander 36 in back of slips 23, so th'at as long as expander 36 is in the extended position, as described, slips 23 will slips 23, the latter cannot be retracted from recess 14 and the anchored engagement is thereby maintained.

When mandrel 35 is moved to'the active or extended position, as described, it will be seen Fig. 4B) that circulation port 42 will have been movedbelow seal 39, thereby closing-off fluid communication between the interior of tubing string 1 and the bore of mandrel 35. Seals 39 and 40 prevent leakage of fluid between mandrel 35 and plug body 18, whilerpacking 29 forms an effective fluid-tight'seal between the plug body and the seatinglnipple, which, of course, constitutes a portion of the tubing string. V

" With the plug member thus effec-tively lodged in the seating nipple, the lowering cable or wire line and its attached tools maybe released'from the plug member by fjarring upwardly through jars -10 against stem 52. 'Ihisjupward jarring action will produce jarring blows betweenshoulder 54 carried by the stem and shoulder 49 in the upper end of connector sleeve 47. jar

.ring. action break shear pin 48, which, secures the connector sleeve 47 to the plug body. When shear pin 48 is thus broken, the string of tools may be withdrawn from the well, leaving the plug device anchored inside the seating nipple (Fig. 6).

The portion of the tubing string above the seating nipple and carrying coupling sleeve 4 may now be disconnected from the lower portion of the tubing string in which the plugging device is lodged by appropriate rotation of the tubing string from the surface to cause release of the bayonet-type connection between the seating nipple and the coupling sleeve. When the upper portion of the tubing string is thus released, it may be withdrawn from the well and operations of any desired character may be conducted within the well bore without danger to the formations which are in communication with the tubing string below the plug.

When it is desired to remove the plugging device from the tubing, the upper tubing section, including coupling sleeve 4, is run back into the well and re-connected to the seating nipple to restore the original continuity of the tubing string. Thereupon a suitable wire line fishing tool of any conventional construction such as is illustrated in broken lines in Fig. 6 and designated generally by the letter F, is run through the bore of the tubing to grasp the upper end of mandrel 35. Cap 43 with its downwardly facing shoulder 44 will provide a suitable fishing head adapted to co-operate with conventional fishing tools, so that the latter may effectively grasp the mandrel. An upward pull applied to man- 'drel 35 by means of the fishing tools, will draw the mandrel .upwardly through the bore of body 18 until shoulder 37 again abuts shoulder 33, whereupon expander 36 will be retracted from engagement with slips 23, the parts being thus returned to their original inactive position illustrated in Figs. 2A and 2B. Continued upward pull applied to the mandrel will pull body 18 and slips 23 upwardly. Engagement of the tapered shoulder 27 on the slips with the tapered upper end wall 15 of recess 14 urge the slips radially inwardly of plug body 18 and out of recess 14, thereby releasing the anchor means from the seating nipple and allowing the plug body to be withdrawn from the well through the tubing string.

The retraction of mandrel 35 to the position last described will re-open communication between circulation passages 32 and 42, and thence through the bore of mandrel 35 through circulation passages 41 and 51, to thereby permit the plug body to be withdrawn without difiiculty.

By positioning the seal packing 29 above the anchor means, it will be seen that a fluid-tight seal may be effected between the upper portion of the plug body and the seating nipple which will efiectively prevent movement of any well liquid through the upper end of the seating nipple and will also prevent the movement downwardly into the seating nipple of any sediment, scale, or other detritus which might result from the jarring action conducted above the upper end of the seating nipple during manipulation of the tool in seating and releasing the plugging device, and will thereby prevent fouling of the anchoring elements, which might otherwise prevent effective operation of the anchoring elements.

The described structure provides particular important advantages over more conventional plugging devices in connection with the removal of the plug in that reopening of the circulation ports to equalize pressures across the plug, and release of the anchoring elements are both effected by a simple upward pull applied through the operating string to the mandrel, thereby avoiding the more complex rotational and other movements ordinarily required in more conventional devices which are a frequent source of difliculty and hazard in operating tools of the kind here involved.

Ports 42 and seal 39 form a sleeve valve for controlling fluid communication through the passage formed by these ports, the bore of the mandrel and ports 41 and 51. When the mandrel is in the raised or inactive position, the valve is open and when the mandrel is in the lowered or active position, the valve is closed.

It will be evident that forms of anchor elements may be employed other than those illustrated by the specific embodiment hereinabove described. It will also be evident that seating nipple 3 may form part of a releasable connection in the pipe string different in form than that illustrated, as for example, a more conventional safety joint commonly used in pipe strings.

It will be understood that various other alterations, modifications and changes may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent is:

l. A bridging plug for closing the bore of a well pipe, comprising, a hollow generally tubular plug body insertible in the bore of a well pipe, radially movable anchor elements mounted in the wall of said body pro jectible therefrom into anchoring engagement with the Wall of the well pipe, tubular mandrel means longitudinally movable in the bore of the plug body into and out of projecting engagement with said anchor elements, a fluid passageway through said body including port means opening to the exterior of the body, valve means carried by the mandrel means operative by the longitudinal movements of the mandrel means relative to said port means to open and. close said passageway, and circumferential seal means mounted on the plug body to seal with the pipe wall above said anchor elements.

2. In combination with a well pipe, a tubular coupling forming a connection between upper and lower sections of said pipe, said coupling comprising upper and lower members and a bayonet-type connector separably connecting said members, and plug means removably insertible in the bore of the lower coupling member to plug the bore of the pipe therebelow, said plug means including radially movable latch elements cooperable with the lower coupling member for releasably anchoring the plug means in the lower coupling member.

3. In combination with a well pipe, a tubular coupling forming a connection between upper and lower sections of said pipe, said coupling comprising upper and lower telescoping members and a bayonet-type connector separably connecting said members, a plug body insertible in the bore of the lower coupling member, means including radially movable latch elements mounted on the body for releasably anchoring the same in the lower coupling member, and circumferential seal means disposed about the plug body to seal with the bore wall of the lower coupling member above the anchor means.

4. In combination with a well pipe, a tubular coupling forming a connection between upper and lower sections of said pipe, said coupling comprising upper and lower telescoping members and a bayonet-type connector separably connecting said members, a hollow generally tubular plug body insertible in the bore of the lower coupling member, radially movable anchor elements mounted in said body projectible therefrom into anchoring engagement with the wall of the lower coupling member, mandrel means longitudinally movable in the bore of the plug body into and out of projecting engagement with said anchor elements, and circumferential seal means disposed about the plug body to seal with the bore wall of the lower coupling member above said anchor elements.

5. In combination with a well pipe extending into a well, a tubular coupling forming a connection between upper and lower sections of said pipe, said coupling comprising upper and lower members, plug means removably insertible in the bore of the lower coupling member to plug the hereof the pipe therebelow, said plug means including radially movable latch elements operable to releasably anchor the plug means in the lower coupling member, and a'readily releasable bayonet-type connector means separably connecting the coupling members whereby the upper section of said pipe may be released from the coupling and withdrawn from the well after said plug means is in place in the lower coupling memberv h 6. A bridging plug for closing the bore'of'a well pipe, comprising, a plug body having a fluid passageway there- 'through 'insentable in the bore of a well pipe, closure means movable "longitudinally in said passageway between a first position opening said passageway to the passage of fluid therethrough and a second position closing said passageway to the flow of fluid therethrough in either direction, anchor means mounted on the body, means connected to theclosure means and operable by movement of said closure means to said second position to move said anchor means to anchor the body to the pipe wall, and circumferential seal means mounted on the plug body to seal with the pipe wall above said anchor means.

7. A bridging plug for closing the bore of a well pipe, comprising, a hollow generally tubular plug body having a fluid passageway therethrough insent able' in the bore of a well pipe, radially movable anchor elements mounted in said body projectible therefrom into anchoring engagement with the wall of the Well pipe, mandrel means longitudinally movable in'the bore of the plug body into and a well pipe, radially movableanchor elements mounted in the wall of said body projectible therefrom into anchoring engagement with the wall of'the well pipe, mandrel means longitudinally movablein thebore of (the plug 'body into and out of projecting' engagement with said anchor elements'to project the latter into anchoring engagement'with the wall of the well pipe, means, carried by the mandrel operable by said longitudinal movements of the mandrel to also open and close said passageway, securing means releasably connecting said' mandrel means to said body in inactive non-projecting position with respect to said anchor elements and releasable for movement to active projecting position relative to said' anchor elements, and circumferential seal means mounted on the exterior of the plug body positioned thereon'to' seal with the wall of the pipe portion above said anchor elements.

7 9. A bridging plugas defined by claim 8 'wherein said mandrel means comprises a tubular member slidably fitted in the bore of said plug body, and wherein annular seal means are positioned between'the mandrel means and the bore wall of'the plug body on opposite sides of said I anchor elements.

References Cited in the of this patent UNITED STATES PATENTS 7 Church Q Jan; 20, 1942 2,737,245 Knox Mar; 6, 1956 

